Clamp assembly for electrical boxes and the like



April 9, 1963 A. l. APPLETON 3,084,958

CLAMP ASSEMBLY FOR ELECTRICAL. BOXES AND THE LIKE Filed March 30. 1960 IN VEN TOR. ARTHUR LAPPLETON aim wvam ATTYS.

United States Patent "ice 3,084,958 CLAMP ASSEMBLY FOR ELECTRICAL BOXES AND THE LIKE Arthur I. Appleton, Northbrook, Ill. (ffi; Appleton Electric Co., 1713 Wellington Ave., Chicago 13, 111.) Filed Mar. 30, 1960, Ser. No. 18,602 1 Claim. (Cl. 285-189) The present invention relates to clamping devices for holding the terminal ends of conduit, cable or tubing and, more specifically, to a novel clamp finding particular utility in securing the ends of cable and conduit within electrical connection boxes.

One object of the invention is to provide a clamp as sembly of the type set forth and which will permit the same to be initially installed and subsequently yieldably held in proper position for use so that all the user need do is tighten the clamping screw.

Another object is to provide a clamp assembly of the above type and having initial positioning means which will be absolutely safe and when put into operation will not interefere with the operation of the clamp or any wiring with which the same may be used.

A further object is to provide a device of the above character and which will be extremely simple and capable of economical manufacture on a mass production basis.

Other objects and advantages will become apparent as the following description proceeds, taken together with the accompanying drawing wherein:

FIGURE 1 is an enlarged perspective view of an electrical connection box including clamping devices which illustratively embody the invention, one side wall of the box being removed for purposes of illustration.

FIG. 2. is a side elevational view of the box of FIG. 1, taken from the removed side.

FIG. 3 is an enlarged fragmentary vertical sectional view through the clamp assembly of the box shown in FIG. 1, such view being taken in the plane of the line 3-3 in FIG. 4.

FIG. 4 is an enlarged plan view of the clamp assembly of the box shown in FIG. 1.

FIG. 5 is an enlarged plan view of the positioning disc of the clamp assembly shown in FIGS. 14, inclusive.

FIG. 6 is an enlarged fragmentary vertical sectional view similar to FIG. 3 but showing a modification of the clamp assembly.

FIG. 7 is an enlarged plan view of the positioning disc of the clamp shown in FIG. 6.

While the invention is susceptible of various modifications and alternative constructions, certain illustrative embodiments have been shown in the drawing and will be described below in considerable detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications and alternative constructions and equivalents falling within the spirit and scope of the invention as expressed in the appended claim.

Referring more specifically to FIGS. 1 to 5, inclusive, the invention is there shown illustratively embodied in an electrical box 82 which in this instance happens to be adapted for housing a switch or receptacle. For the purpose of anchoring one or more terminal ends of cable 3,084,958 Patented Apr. 9, 1963 or flexible conduit within the box, clamp assemblies 81 are provided, one such assembly being adjacent each pair of knockout openings 83 in the back wall panel 88 of the box. Each clamp assembly comprises a jaw 84 having a pair of integral arcuate shoes 85 for engaging the cable or conduit and a stiffening wing 86 disposed at an obtuse angle to the plane of the shoes 85. The wing 86 may also have a slightly downturned edge portion adapted to bear against the back wall of the box as the jaw 84 is tightened. The jaw 84 is mechanically connected to the back wall 88 of the box by means of clamping screw 89. The latter extends slidably through an opening 90 and engages a tapped hole 91 in the back wall of the box.

For initially positioning the clamping jaw 84 in the box in proper position for use and firmly but yieldably holding the jaw in such position, the assembly 81 is provided with a positioning disc 92. The latter is adapted to yieldably engage the mounting screw 89 after the manner of the discs 40, 49 and 71 described earlier herein. For this purpose, the disc 92 (FIG. 5) has a central aperture 94 and a plurality of radial slits 95 defining a corresponding plurality of prongs 96. To etiect positive engagement between the disc 92 and the jaw 84, the disc is provided with diametrically opposed, outwardly extending tabs 98. The latter are adapted for insertion into a corresponding pair of slots 99 situated in the jaw 84 on either side of the central screw opening 90. With this arrangement, the disc 92 is positively prevented from rotation relative to the jaw 84 upon tightening of the clamping screw 89. While the disc 92 has been illustrated in a position between the upper face of the jaw 84 and the head of the clamping screw 89, it will be appreciated that the disc could also be positioned under the lower face of the jaw and perform satisfactorily.

Turning next to FIGS. 6 and 7, there is shown a further modified clamp assembly 100 somewhat similar to the assembly 81 just described. In this instance, the assembly 100 includes a jaw 101 similar to the jaw 84 and which is mechanically connected to the back Wall 102 of the box by means of a clamping screw 104. The jaw 101 in this instance is yieldably positioned on the clamping screw 104 by means of positioning disc 105 generally similar to the discs described earlier herein. In this instance, however, the assembly depends simply upon frictional contact between the disc 105 and the underside of the jaw 101 to oppose the tendency for relative rotation upon tightening of the clamping screw 104.

I claim as my invention:

In an electrical connection box having a wall with openings therein for receiving the terminal ends of cable or flexible conduit, a clamp assembly comprising, in combination, a clamping jaw having a screw opening therein, said jaw having a pair of diametrically opposed slots therein on either side of said screw opening, a clamping screw having a head and a shank, said clamping screw being disposed with its shank projecting through said screw opening and into threaded engagement with said box wall, a positioning disc of relatively resilient material having an aperture receiving said screw shank, said disc having a plurality of circumferentially spaced slits radiating from said aperture and defining therein a plurality of prongs, said disc being positioned with said prongs coplanar with the remainder of said disc and in yieldable threaded engagement with said shank, and a 3 pair of diametrically opposed tabs integral with said disc,

saidv disc being positioned on said screw shank with one face thereof in contact with said jaw and with said tabs positively locked in said slots, whereby relative rotation between said jaw and said disc is precluded.

References Cited in the file of this patent UNITED STATES PATENTS 256,149 Long Apr. 11, 1882 1- Frick July 11, 1906 Meachurn Feb. 23, 1909 Fisher Dec. 28, 1926 Thomas July 8, 1930 Cook Dec. 2, 1930 Washer Oct. 17, 1939 Carlson Mar. 2, 1948 Riddle Dec. 15, 1959 

